The present invention relates generally to methods and apparatus for accurately delivering precisely metered amounts of particulate material repetitively during high speed manufacture of particulate bearing articles of manufacture, more particularly, to precise, repetitive delivery of granular particles such as charcoal and/or silica gel or other material to spaced locations along a continuous, moving stream of bundled filaments comprising cellulose acetate or other forms of tow.
Certain articles of manufacture such as particle bearing cigarette filters, individual-sized packets of granular food products or condiments, capsuled pharmaceuticals, ammunition and the like require repetitive placement of precisely metered charges of particulate matter at some location along the production-line procession of the articles. Difficulties arise in pursuing sufficient speed in the mass production of such articles without sacrificing consistency, damaging the material and/or exacerbating spillage, particularly at elevated manufacturing speeds where ricochet and vibration may impair process control and consistency.
With machines of the prior art, process control usually suffers at high machine speeds from inconsistent metering and pulverization of the material, particularly in those prior machines where fast moving machine components are allowed to impinge stationary or relatively slow moving particulate material. For example, certain prior particle metering devices contain a supply of particle in a hopper and allow the rim of a rotating metering wheel to rotate through the relatively stationary collection of particle. Such an arrangement creates a pulverizing action upon the particle which generally increases with machine speed.
Excessive pulverization of the particulate material may alter the qualities of the final product unacceptably. Ricochet and escape of particulate matter during manufacturing operations with prior machines often create unacceptable deficiencies in the final product (such as smears or incomplete fillings) and precipitate undesirable machine xe2x80x9cdown-timesxe2x80x9d to effect clean-up of the machine and the surrounding work environment.
It is also known from the prior art that the manufacture of cigarette filters, particularly the commonly used cigarette filters made of a cellular acetate tow, that the processing of the tow presents various difficulties. For example, the tow has very little tensile strength and, therefore, special handling techniques must be devised to avoid stretching the tow. Further, when drawing the tow around rollers, the fibers of the tow furthest from the roller tend to be stretched relative to the fibers closest to the roller. After the tow has passed the roller, the stretching of the fibers tends to cause the tow to remain in a curved or bent condition.
It is known to apply a plasticizing agent to fibrous cellulose acetate during production of filter rods. It is further known from the prior art that application of plasticizer material close to particulate material in cigarette filters can case at least partial deactivization of the particulate material if the plasticizer migrates to the particulate material.
An object of the present invention is to provide a method and apparatus capable of precisely metering discrete amounts of particular material at high machine speeds.
Another object of the present invention is to provide a method and apparatus which executes high speed delivery of metered amounts of particulate material without pulverization of the material even at high operational speeds.
Yet another object of the present invention is to provide an apparatus for delivering particulate material, which minimizes shearing action upon the particulate material.
Still another object of the present invention is to provide a method and apparatus which minimizes shear upon the particulate material by maintaining low relative velocities between the particulate material and portions of the machine coming into contact with the particulate material.
Another object of the present invention is to provide a method and apparatus which transfers particulate material with the assistance of vacuum so as to minimize scatter and promote consistency even at high machine speeds.
Still another object of the present invention is to provide a method and apparatus for high speed delivery of particulate material with minimal escape of the material.
Yet another object of the present invention is to provide a method and apparatus for accurately delivering precisely metered amounts of particulate material repetitively during high speed manufacture of particulate bearing articles of manufacture, and most particularly, to precise, repetitive delivery of granular particles such as particle and/or silica gel or other material to spaced locations along a continuous, moving stream of bundled filaments comprising cellulose acetate or other forms of tow.
Still another object of the present invention is the provision of method and apparatus that permits low tensile strength material such as cellular acetate tow to be processed under minimal tension.
Still another object of the present invention is the provision of a method and apparatus that permits low tensile strength material such as cellular acetate tow to be processed in equipment having rollers around which the tow travels without causing excessive stretching of the tow so as to minimize tendency of the tow to retain a bended shape.
Still another object of the present invention is the provision of a method and apparatus for making a cigarette filter in which precisely metered amounts of particulate material are delivered and retained in a continuous filter rod in which plasticizer is applied to the cigarette filter at locations remote from the particulate material.
These and other objects are achieved with the present invention which is embodied in an arrangement for the production of particle bearing cigarette filters. Such apparatus and method includes a tow treatment apparatus arranged to produce a continuous stream of fibrous material; a fibrous rod maker at a second location downstream of the tow treatment apparatus for wrapping the plug wrap about the continuous stream of fibrous material and sealing same; a particle inserter operative at a location between the rod maker and the tow treatment apparatus for inserting predetermined, metered amounts of particles in spaced, discrete locations along the continuous stream of fibrous material; and a cutter downstream of the filter rod maker for cutting the continuous, particle bearing, fibrous rod into discrete rod plugs.
In particular, the particles are delivered by first establishing a continuous stream of fibrous material along a feed path; establishing a flow of particles along a first path; moving a first pocket along an endless path at least partially coinciding with the first path; drawing an amount of the particles into the pocket as the pocket moves in proximate relationship with the particles flow; transferring the drawn amount of particles from the first pocket to a second pocket while moving the second pocket along a second endless path which coincides with the feed path at a release location; forming a pocket-like recess in a portion of the continuous stream of fibrous material adjacent the release location; releasing the drawn amount of particles from the second pocket into the recessed portion of the continuous stream of fibrous material at the release location; and subsequently closingly folding adjacent portions of the continuous stream of fibrous material about the released, drawn amount of particles.
Preferably, particles are retained with the assistance of vacuum application to the pocket-like recess at the release location and at least during a first portion of the closing step.
In addition, or in the alternative, a filter bearing spaced-apart amounts of plasticizer can be manufactured by a method and in a system wherein a continuous strand of fibrous material is established, the continuous strand of fibrous material is moved past a plasticizer delivery point, and a plasticizer is intermittently applied to the continuous strand of fibrous material at application points on the continuous strand of fibrous material as the application points move past the delivery location. Vacuum is communicated to the locations so as to promote migration of plasticizer into the tow at the locations and to limit migration of the plasticizer outside of the locations.
These and other objects and advantages of the invention will become apparent upon the consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which each particular reference numeral consistently refers to particular parts throughout. The following figures are included:
FIG. 1 is a schematic side view of a filter rod maker system constructed in accordance with an embodiment of the present invention;
FIG. 2 is a schematic side view of a preferred particle charger apparatus of the filter rod maker of FIG. 1;
FIG. 3A is a detailed, partially cut-away side view of the metering wheel of the particle charger apparatus of FIG. 2;
FIG. 3B is a detail view along arrow B in FIG. 2;
FIG. 3C is a sectional detail taken along line Cxe2x80x94C in FIG. 3A;
FIG. 4 is another detail view along arrow B in FIG. 2;
FIG. 5 is a schematic side view of portions of a filter rod maker system constructed in accordance with another preferred embodiment of the present invention;
FIG. 6 is a perspective view of an optional transfer jet useful in the systems shown in FIGS. 1 and 5;
FIG. 7 is a cross-sectional side view of a 4-up cigarette filter plug constructed in accordance with systems such as shown in FIGS. 1 and 5;
FIG. 8 is a cross-section as viewed from line 7xe2x80x947 in FIG. 7;
FIG. 9 is a filter cigarette constructed in accordance with a preferred embodiment of the present invention;
FIG. 10 is a schematic side view of a filter rod maker system constructed in accordance with another embodiment of the present invention; and
FIG. 11 is a cross-sectional side view of a 4-up cigarette filter plug constructed in accordance with systems such as shown in FIG. 10;
FIG. 12 is a schematic, partially cross-sectional, side view of a plasticizer application station according to an embodiment of the present invention;
FIG. 13A is a schematic, perspective view of a portion of a plasticizer application station according to an embodiment of the present invention;
FIG. 13B is a schematic, partially cross-sectional view of a plasticizer application station according to an embodiment of the present invention;
FIG. 14 is a schematic, perspective view of a portion of a plasticizer application station according to an embodiment of the present invention;
FIG. 15 is a schematic, perspective view of a portion of a plasticizer application station according to an embodiment of the present invention
FIG. 16 is a schematic, side view of a portion of a plasticizer application station according to an embodiment of the present invention;
FIG. 17A is a schematic, side view of a portion of a plasticizer application station according to an embodiment of the present invention;
FIG. 17B is a schematic, frontal view of a slotted rotatable drum according to an embodiment of the present invention;
FIG. 18A is a side view of folding rollers according to an embodiment of the present invention; and
FIG. 18B is a top view of folding rollers according to an embodiment of the present invention.